Well you can have lots of tropical fish live together. You just base them on their level of aggressiveness, so cichlids are pretty aggressive, so you only house them with other aggressive fish. For 10 gallons, your choices are limited. You can't have any cold water fish, as the tank is way, way, too small for gold fish, fantales etc. They need at least 30 gallons for one, plus another 10-15 for each next fish. So you have to go with tropical fish, as you can get smaller ones that will only grow a few inches such as neon tetras, other tetras, mollies, platys, guppies. The last three are more suited to 15 gallons, but you could probably put 3 in a 10 gallon, baring in mind they are live bearers and they will breed like we breathe air. You could probably put 4 neon tetras in with 3-4 cherry barbs, and a few rasboras. Or you could get some zebra danio's. They will all go well in a tank together.
